Pressing apparatus



April 7, 1942. f.

.L 1 DRAKE Er AL PRESSING APPARATUS Filed May 28, 1957 2 Sheets-Sheet 1/NVENTo/eo e/oH/v L. DFA/(E.

GEORGE WA TK/Ns.

ATTORNEY 2 sheets-sheet 2 Y PRESSING APPARATUS Filed May 28, 1937 J. L.DRAKE ETAL.

GEO/PGE WHT/(ING.

' A T T ORNE Y B Y y n April 7, 1 942.

Patented Apr. 7, 1942 PRESSING APPARATUS John L. Drake and George B.Watkins, Toledo, hio,-assignors to Libbey-Owens-Ford Glass Company,Toledo, Ohio, a corporation of Ohio Application May 28, 1937, SerialNo..145,228

3 Claims.

The present invention relates to the manufacture of laminated safetyglass and more particularly to an improved pressing apparatus for use inthe compositing of the laminations.

Generally speaking, laminated safety glass comprises two or more sheetsof glass and one or more non-brittle membranes or plastic sheets allbonded together' to form a composite structure. In manufacturing thistyp'e of safety glass, itis customary to first assemble the variouslaminations in proper superimposed relationship, after which they arebonded together by subjecting the glass-plastic sandwich to the actionofl heat and pressure.

According to one method of manufacture, an ordinary roll type press isused for this purpose. However, in using such a construction for bondinglaminated safety glass, considerable diiculty is encountered because ofthe unequal distribution of pressure on the sandwich as it passesbetween the rolls, which unequalpressure results in a flexing of theglass sheets. Further, since this iiexing action is accentuated withincreased plasticity of the plastic used, it will be apparent that withthe advent of softer plastics, particularly those made from the vinyltype of resin such as Formvar, Alvar, and Butylvar, the difficulty iseven more pronounced because of the greater plasticity or lack ofrigidity of these resin type plastics.

y It is therefore an important object of the present invention toprovide a pressing apparatus of novel and improved construction whereinthe assembled laminations forming the glass-plastic sandwich may berapidly and eiliciently bonded together in a continuous manner by rollpressure and wherein the pressure applied to opposite surfaces of thesandwich will be distributed unlformly throughout their entire areas,thereby minimizing, if not entirely preventing, flexing of the glasssheets during the pressing thereof.

Another object of the' invention is the provision of apparatus of theabove character wherein the pressing of the glass-plastic sandwich iseffected by passing it between a plurality of pairs of relatively smallpressure rolls which are positioned relatively close together andwherein compressible cushions or pads are arranged between the pressurerolls and glass-plastic sandwich to distribute the pressure exerted bysaid rolls uniformly throughout the opposite surface areas of saidsandwich.

Still another object ofthe invention is the provision, in apparatus ofthe above character, of novel means for preventing the bending ordistortion of the small pressure rolls and consequent bending of theglass sheets.

Other objects and advantages of the invention will become more apparentduring the course of the following description when taken in connectionwith the accompanying drawings.-

In the drawings wherein like numerals are em- A ployed to designate likeparts throughout the same;

Fig. 1 is a longitudinal vertical sectional view through an apparatusconstructed in accordance tion, taken substantially on line 4-4 in Fig.2

and l Fig. 5 is a fragmentary sectional view of a iinished sheet oflaminated safety glass.

Referring now more particularly to the drawings, the preferred form ofpressure apparatus herein provided for carrying out the. presentlnvention includes an improved type of roll press designated in itsentirety by the numeral I0 and which is housed within a suitableenclosure II. The enclosure I I comprises a rectangular tank I2 and ahood or cover I3 arranged .thereabove and provided centrally thereofwith a stack I4. The tank I2 is preferably formed with relativelyshallow portions I5 and I6 at its opposite ends and a relatively deeperintermediate or middle portion Il with which the press I0 is associated.

The press I0 includes a pair of horizontally arranged, superimposed,endless belts I8 and I9 between which the glass-plastic sandwiches 20are adapted to move during the pressing operation. The lower belt I8 istrained about spaced drums 2l and 22 keyed to shafts 23 and24respectively, the opposite ends of said shafts extending throughsuitable packing glands in the opposite Iside walls of the tank I2 andbeing journaled in elongated bearing blocks 25 and 26 which are withbosses 34 and` 35 respectively having vertical openings therein toreceive threaded vertical rods 36 and 31 which are rigidly secured tothe blocks able relative lto the bearing blocks 35 and 36, be-

ing limited in their downward movement by stop nuts 33 and 36 threadedupon the rods v36 and 31. Suitable tighteners 45 and 4I are provided forthe belts `I5 and I3 respectively and kthese tighteners also serve tomaintain the loops of the belts open as shown in Fig. 1.

In order to support the glass-plastic sandwiches as they move betweenthe belts I3 and Il and to simultaneously apply pressure thereto, thereis provided the oppositely disposed roll assemblies 42 and 43 associatedwith the belts I3 and I9 respectively. The lower roll assembly 42 ispositioned within the loop of the lower belt I3 and is adapted tosupport the upper run thereof while the upper roll assembly 43 isarranged vwithin the loop of the upper belt I9 and engages the lower runthereof.

'I'he roll assemblies 42 and 43 include a plurality of relatively small,horizontally aligned pressure rolls 44 and 45 respectively which areprovided Vwith the respective stub shafts 46 and 41. I'he ends of thesestub shafts extend through packing glands 41' in the side walls of thetank I2, the shafts 46 of the rolls 44 being journaled in the bearingblocks and 26 while the shafts 41 of the rolls 45 are journaled in thebearing blocks 32 and 33. As best shown in Fig. 4,'the individualpressure rollsof each of the roll assemblies 42 and 43 are positioned asclose together as is practicable without their being in actual contactwith one another and each of the rolls 44 of the lower assembly 42 isarranged directly below a corresponding roll 45 of the upper assembly 43and isadapted to coact therewith, thus providing a plurality of closelyspaced pairs of oppositely disposed pressure rolls between which .theglass-plastic sandwiches 26 are pressed.

As set f orthabove, the pressure rolls 44 and 45 are preferably maderelatively small, for example about one inch in diameter, and thispermits the positioning 'of the pressure rolls to exert pressure alongclosely spaced transverse lines for the purpose of providing a morenearly continuous pressing surface. In order to prevent any ing use andwhich would result in an unequal of the large backing up rolls 46 willbe in rol1lng` contact with two adjacent intermediate rolls 5I so thateach of the intermediate rolls vwill be contacted by one of the backingup rolls.

The construction of the roll assembly 42 in this manner not only makespossible the use of large backing up rolls for the small pressure rolls,but has the additional advantage of reinforcing the pressure rolls attwo spaced points on their peripheries which reinforcement willeiectually prevent the bending .or distortion of these pres. sure rollswhile in use.

'I'he vconstruction of the upper roll assembly 43 is similaigto that ofthe lower roll assembly 42 and includes similar backing up rolls 53 andintermediate-rolls 54 mounted and positioned in a similar mannerrelative to the pressure rolls 45. This particular arrangement of thedifferent rolls in the assembly also permits each roll to rotate withoutfriction with the other rolls due to the distribution of pressuretransversely of the sandwiches, the present invention contemplates theprovision of relatively large backing up rolls associated with the smallpressure rolls of each roll assembly in a manner to prevent the bendingor distortion of these pressure rolls. Thus, the

tween the pressure rolls 44 and the backing up ro1ls46. 'I'heseintermediate rolls 5I are pref.-

erably of substantially the 'same size as the pressure rolls 44 and aremounted in a similar-manner, being provided with stub shafts 52 passingthrough packing glands inthe side walls of the tank I2 and journaled inthe bearing blocks 25 and 25. The arrangement of the various rolls inthe lower roll assembly 42 (Fig. 4) is suchv that 75 bearing blocks 32and 33 form the upper halt of the pressing apparatus which is verticallymovable upon the rods 36 and 31 relative to the lower half of thepressing apparatus. s

In order that the oppositely disposed pressure rolls 44 and 45 willexert the desired pressure upon the sandwiches 20 as they move betweenthe belts I6 and I3, there are provided the compression springs 55 and56 encircling the vertical rods 36 and 31'respectively between thebosses 34 and 35 and pressure regulating nuts 51 and 53. The compressionsprings 55 and56 will act to urge the bearing blocks 32 and 33andconsequently the pressure rolls 45 downwardly toward the rolls 44 toexert the necessary pressure upon the sandwiches passing therebetween.'I'he amount of pressure exerted by the pressure rolls.

upon the sandwiches may be controlled by adjusting the nuts 51 and 56and thesenuts may Y be adjusted so as to give a differential in pressurebetween the springs` 55 and springs 56, thus causing the pressure rolls44 and 45 to exert progressively increasing or decreasing pressure fromone end of the apparatus to the other.

I'he use of small pressure rolls in pairs posi.,V

tioned close together as described above -will assist in overcomingtheunequal distribution of Pressure upon the sandwiches as they passbeinterposed between the pressure rolls and the sandwiches.

compressible material which is adapted to-'yi'eld 'I'hese belts are madeof a resilient to the pressure of the rolls 44 and'45 in a manner todistribute the pressure' exerted thereby uniformly over the entiresurface areas of the sand-I wiches. As clearly shown in Fig. 4, each ofthe layer a being of a highly resilient, compressible material such assoftrubber while the inner layer b is of a material which is resilientand compressible but non-stretchable such as a rub.- ber and fabriccombination. vDue to this construction and arrangement, the belts I8 andI9 will act to distribute the pressure exerted by the rolls 44 and 45'uniformly throughout the surface areas of the sandwiches to provide asubstantially equal pressure at all points but will not be pulled orstretched out of shape during the operation of the apparatus.

In order to convey the sandwiches to be pressed through the pressingapparatus, the belts IB and I9 are adapted to be driven by means of thedrums 22 and 29 respectivelywhich are in turn positively driven by vthechain and sprocket drives 59 -and 60 respectively operativelyAassociated with one end of the shafts 24 and 3I and connected to asuitable source of power. It is also desired that each of the rollswhich comprise the roll assemblies 42 and 43 be positively driven at aperipheral speed substantially the same as the speed of the belts I8 andI9.

To this end, there is associated with the outer end of one of the stubshafts 49 of each of the backing up rolls 48 of the lower roll assembly42 a chain and sprocket drive 6| which may be connected to the samesource of power as the chain and sprocket drives 59 and 6I) for thebelts I8 and I9, and keyed to the shafts 49 of the rolls 48, inwardly ofthe chain and sprocket drive 6I, are spur gears 62. One of the stubshafts 52 of each of the intermediate rolls I is also provided adjacentits outer end with a spur gear 63 and a similar gear 64 is keyed to theouter end of one of the stub shafts 45 of each ofthe pressure rolls 44.

Each of the gears 63 associated with the interthe gears 52 associatedwith the backing up rolls 48 and' with two ofthe gears 64 associatedwith the pressureI rolls 44. In other words, each intermediate roll 5Ihas associated therewith a gear p 63 whichis adapted to mesh with thegear 62 and the two gears 54 which are associated with the backing uproll 48 and the pressure rolls 44 respectively with which the saidintermediate roll is in rolling contact.

Since the size of the gears 62, 63 and 64 is proportionate to the sizeof the rolls 48, 5I and 44 For the purpose of heating the sandwiches 20as they pass through the pressing apparatus, the

. tank I2 may be filled with a suitable liquid 69 which is adapted to beheated by means of a temperature controlling medium such as steam orgradually raised by increasing the temperature' `mediate rolls 5I isadapted to mesh with one of the press III.

jected to the temperature thereof.

The temperature of the sandwiches may be of the medium circulatedthrough the conduits I0 from the forward to the rearward end of the tankI2, and in order to more accurately control the temperature ofthe'liquid throughout the length of the tank there is provided a seriesof partition walls I I' extending transverselythereof.

Although the heating means described above is the preferred form, itwill be understood that various other `methods may be employed forheating the`- sandwiches. i For example, satisfactory resultsmay beobtained by blowing heated air upon the moving belts I8 and I9.

While the pressure apparatus of the present invention is in no wayrestricted to use in the bonding together of any particular type ofglassplastic laminations or to any particular process for so'doing, itis especially well adapted for use in the manufacture of laminatedsafety Aglass which includes a sheet or layer of plastic made from thevinyl type of resin such as Formvar, Alvar, and Butylvar for -thereasons explained above.

In manufacturing this type of laminated safety glass, as the sandwiches,pass through the pressing apparatus, the temperature of the sandwich isgradually raised to the point necessary for bonding the laminations. Asthe temperature of the resin plastics is increased, their softness orowability increases, and it is desirable to apply the maximum pressureto the sandwich as it enters the press and to then gradually decreasethe pressure as the temperature increases in order 'to prevent flowingor extruding of the plastic and thereforeA pinching of the lamlnationsaround their edges.

Therefore, in pressing sandwiches including this type of plastic, thenuts 51 and 58 are adiusted to provide a gradually decreasing pressurefrom the forward to the rearward end of The various laminations formingthe sandwiches 20 are arranged in proper superimposed relationship andplaced initially upon a conveyor 12 which moves them to the forward endof the tank I2. The sandwiches are then received upon a feeding conveyor13 arranged within the tank and which includes a. plurality of rollswhich are positively driven at the same rate of speed as that of thebelts I8 and I9 and so arranged that the sandwiches are rst caused tomove downwardly at anangle until they are immersed within the liquid59and then in a horizontal direction to feed them into the press I0between the belts I8 and I9.

As the sandwiches enter the press I0 they will be at or below normalroom temperature. and as thevmaximum pressure isvexerted thereupon bythe pressure rolls 44 and`45, the air and noncondensable gases will beswept from between hot water circulated through spaced conduits I0disposed within` the liquid 69 and extending transversely of the tankI2. As shown in Fig. 1 of the drawings, the 'press I0 is so arrangedwithin the tank I2 that the upper run of the lower belt'l8 and the lowerrun of the upper belt I9 are below the level of the liquid 69 so thatthe sandwiches passing between the belts will be the laminations.- Then,as the sandwiches proy gress through the press, the temperature thereofwill be gradually raised by means of the heated liquid 69 to the pointnecessary for bonding the laminations while the pressure upon thesandwiches will be gradually decreased. As the treated sandwiches issuefrom the press I0, they will be received upon a discharge conveyor 'I4and caused to-move first in a horizontal direction and then upwardly atan angle until they are out of the liquid 69, after which they will bedischarged from the tank upon a conveyor 15.

Although only a single pressing unit I0 has units arranged in horizontalalignment to operate as a single pressing apparatus may be if desired.Further, the sandwiches may also be cooled under pressure before beingdischarged from the apparatus if preferred.

In Ilig.y there has been illustrated a fragmentary section of a finishedsheet of laminated safety glass formed in accordance with the presentinvention and which includes two sheets of glass 1| and 11 and aninterposed sheet of plastic material 18.

It is to be understood that the form of the invention herewith shown anddescribed is to be Y taken as the preferred embodiment of the same. andthat various changes in the shape. size'and arrangement of parta mayberesorted to without departing from the spirit of the invention or thescope of the subioined claims.

We claim:

1. In apparatus for compositing laminated safety glass, a plurality ofpairs of relatively small pressure rolls arranged relatively close toone another and between which the 'glass-plastic sandwiches to bepressed are adapted to be passed, cushioning means for receiving thepressure exerted by the pressure rolls and distributing said pressureover the cppositefsurfaces of said sandwiches. relatively large backingup rolls associated with the small pressure rolls, and intermediaterolls positioned between said backing up rolls and said pressure rollsto permit each backing up roll to back up a plurality 0I adjacent smallpressure rolls.

2. Inapparatus for compositing laminated safety glass, a .plurality ofpairs of relatively small pressure rolls arranged relatively close toone another and between which the glass-plastic sandwiches -to bepressed are adapted to be Y passed, 'cushioning means for receiving thepressure exerted by the pressure rolls and distributing said pressureover the opposite surfaces of said sandwiches, relatively large backingup rolls associated with the small pressure rolls, and intermediaizevrolls positioned between said backing up rolls and said pressure rolls,each of said intermediate rolls being in rolling contact with twadjacent pressure rolls and one backing up ro v 3. In apparatus forcompositing laminated safety glass. a plurality oi.'V pairs ofrelatively Asmall pressure rolls 'arranged' relativelyclose to oneanother and between which the glass-plastic sandwiches to be pressed areadapted to be y passed, cushioning means for receiving the pressureexerted by the pressure rollsand distributing said pressure over theopposite surfaces of said sandwiches, relatively large backing up rollsassociated with the small pressure rolls. and intermediate rollspositioned between said backing up rolls and said pressure rolls topermit each v backing up roll to hack up a plurality of adjacent smallpressure rolls. each oi' said pressure rolls being contacted by twointermediate rolls. y

JOHN L. BRAKE. GEORGE B. WATKINS.

